The present invention relates to an inflatable cushion that incorporates a resistance wire to facilitate sealing the inflatable cushion.
Packagers are increasingly using air-inflated cushions formed from relatively thin films of thermoplastic to protect their packaged goods within boxes, sleeves, or cases during shipping and storage. For example, an inflatable packaging cushion system that can protect a wide variety of packaged goods is sold by Sealed Air Corporation under the VISTAFLEX trademark. The VISTAFLEX inflatable packaging cushion includes an inflation inlet designed for use with an inflation/sealing machine provided by Sealed Air Corporation under the BT-1 trademark. As depicted in FIG. 1, the inflation inlet 12 of the inflatable cushion 10 has top and bottom sheets 14, 16 sealed at the peripheral zone 18 to form an inlet passageway 20. The BT-1 inflator/sealer controls both the inflation of the cushion with compressed air and sealing of the inflated cushion with an impulse heat sealer.
To inflate and seal the VISTAFLEX cushion, a user inserts the inflation tube 22 of the prior art inflator/sealer (not shown) into the inflation inlet 12 of the cushion 10. (FIGS. 2-3.) The inflator/sealer inflates the cushion by opening a valve to allow compressed air to pass through the inflation tube 22 into the interior of the cushion chamber 24 until the cushion chamber has been inflated to the desired pressure. (FIG. 4.) At that point, a heat seal bar 28 compresses the top and bottom sheets of inlet 20 to prevent the inflated cushion from deflating. (FIG. 5.) The heat seal bar includes heating element 28. An electric current passes through the heating element 28 to heat the element, which then conducts heat to the compressed top and bottom sheets of the inlet until the sheets reach the heat seal initiation temperature. The electric current is then discontinued to heating element 28 to allow it to cool while the heat seal bar continues to compress the top and bottom films. Once the resulting heat seal has cooled to the point where the heat seal is set, the heat seal bar 26 disengages. (FIGS. 6-7.) The resulting heat seal 30 is formed transversely across inlet passageway 20 to seal cushion chamber 24 in the inflated state.
The BT-1 inflation system allows a packager to inflate and seal inflatable packaging cushions in a consistent, reliable, and easy manner at the site where the goods are to be packaged. For example, the BT-1 machine may complete an inflation and sealing cycle for a packaging cushion in about 8 seconds. Nevertheless, packagers desire an even faster and more reliable system for inflating and sealing inflatable packaging cushions.